TromboneChat

Hope this link comes through. Not my horn, I was just strolling through ads and noticed this newish Bach 16, and what looks like red-rot, or some type of corrosion, on the nickle-silver outer slide. (Pics 5+6)
What gives? Even if it was not well maintained (kept clean) it does not seem as if this should happen in just a few years.

You can see problems on the bell too. That's not corrosion, and it's certainly not red rot. It's a lacquer problem.

I agree that does not look like red rot. What it looks like is a really poor lacquer application.

OK. I jumped to a conclusion there. Still, it doesn't seem like a new-ish trombone should have lacquer issues like that. Hope it's not common, although it should be covered by the warranty.

Dezincification (red rot) does not occur in nickel silver. Looks like either a contaminant on or under the lacquer.

Looks like either something messed with the lacquer, or the horn was not cleaned properly before lacquer. Also depends on how it has been stored, used, etc.